It hasn't started since removing the tank and adjusting the valves. The valves seem easy enough to adjust but one adjuster didn't really slide back and forth too easily. I sprayed it and loosened it up and readjusted it a few times the other night. Didn't seem to make any difference.
How does the petcock get stuck in the closed position? Like an airlock, is that what you mean? That sort of seems more likely the issue. It did happen after removing and remounting the tank and hoses.
“A gentleman is someone who can play the accordion, but doesn't.”
― Tom Waits